Flow divider



July 19, 9 e. K. NELUHAUS I 29 5 v IFLOW'DIVIDER FildMay 26, 1955 I From ihe'moinlin behind #he restrictor -From ihe main line ahead of the restricior Measuring Device IN V EN TOR.

GUSTAV K.NEUHAUS United States Patent FLOW DIVIDER Gustav K. Neuhaus, Sundernholz 20, Essen-Stadtwald, Germany Filed May 26, 1955, Ser. No. 511,335 Claims priority, application Germany June 3, 1954 8 Claims. c1. 137-505.13)

The present invention relates to flow dividers especially for use in connection with measuring operations.

It is an object of this invention to provide an improved flow divider in which the precision ofthe measurements will not be affected by the static pressure in the main line.

It is another object of this invention to provide. an improved flow divider in which a branch current is branched off from the main line which branch current will be proportional to the flow in the main line.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

Fig. 1 represents an axial longitudinalsection through a first embodiment of the invention.

Fig. 2 is a modification of a part of the arrangement shown in Fig. l.

. Fig. 3 is a further modification of a part of the arrangement shown in Fig. 1. i 1

One of the primary features of the present invention consists in that the branch current behind the valve of the flow divider is subjected to a pressure head. This pressure head may substantially be proportional to the static pressure in the main line. According to a further feature of the invention the arrangement is such that the pressure head is made ineffective when the static pressure is so low that the discharge velocity at the valve of the flow divider drops below sound velocity. More specifically, the flow divider valve is followed by a stop valve which is subjected to the pressure ahead of the flow divider valve in closing direction of said valve, the closing force being smaller than the force required to open said valve by the branch current.

Referring now to the drawing and Fig. 1 thereof in particular, the flow divider shown therein comprises a casing composed of the major part 1 and smaller part 2. Each of the parts 1 and 2 is provided with a chamber 4 and 5 respectively which chambers are separated from each other by a diaphragm 3 interposed between the parts 1 and 2. The parts 1 and 2 are respectively provided with bores 6 and 7 arranged for respective connection with the main line ahead and behind the restrictor furnishing the effective pressure head. The flow divider furthermore comprises a valve body -8. The part 1 is provided with a bore 9 in which is arranged a stopper 10 the upper portion of which carries the valve seat 11.

The stopper 10 is provided with a bore 12 by means of which the chamber 4 communicates with a chamber 13 formed by the lower portion of the bore 9. A passage 14 leads from the chamber 13 toward the outside of the part 1 and is adapted to be connected to the measuring instrument for instance a gas meter. Below the chamber 13 and in spaced relationship thereto there is provided a chamber 15 closed by a stopper-16; The chamber 15 communicates through a bore 17 with the chamber 4 and furthermore communicates through a bore 18 with the chamber 13. A plunger 19 extends throughand is guided by the bore 18. This plunger 19 may be additionally 2,945,507 Patented July 19, 1960 sealed by a lip-shaped seal or the like 20. The upper end of the plunger *19 may support a cup 21 which latter carries therein a valve body 22. The seat 23 for the valve body is formed by the lower end surface of the stopper 10. Small helical springs 25 are located in bores 24 of the stopper 10. These helical springs 25 continuously urge the valve body 22 away from its seat 23. The cross section of the bore 18 is somewhat smaller than that of the bore 12.

If the quantity of medium passing through the main line is to be measured and a high static pressure is en countered in the main line and if the flow divider valve 8, 11 opens at this flow in view of the difference in pressure ahead and behind the restrictor, with the heretofore known embodiments of flow dividers a suction elfect is created which will attract to the valve seat 11 the valve body 8 together with the diaphragm 3 thereby reducing the indicated measurement. In order to avoid this drawback, according to the present invention the fluid flow divider valve is behind the branch current subjected to a pressure head. To this end there is provided valve 22, 23 which henceforth will be called the pressure head valve or stop valve. When the pressure in chamber 4 increases, the pressure in chamber 15 will likewise increase in view of the fact that both chambers, 4 and 15 communicate with each other through the bore 17. As a result thereof, the plunger 19 will be pressed upwardly inasmuch as only a low pressure in chamber 13 will prevail ahead of the measuring instrument. Due to the upward movement of the plunger 19, the valve body 22 is pressed against its seat 23 at a pressure which will be proportional to the static pressure in the main line provided that the pressure difference at the effective pressure producer or restrictor is neglected. Inasmuch as the cross section of the plunger 19 is smaller than the effective cross section of the valve 22, 23, the force tending to close the valve 22, 23 is less than the force required for opening the valve and represented by the branch current flowing through the bore 12. By properly selecting the ratio of the cross section of the plunger 19 to that of the bore 12, with each higher pressure, a lower pressure drop and thus a lower suction can be obtained so that the measuring result will not be affected. If the static pressure in the main line drops considerably, for instance down to from 2 to 1 atmospheres above atmospheric pressure, the discharge velocity at the fluid flow divider valve 8, 11 will drop below the sound velocity, and the stop valve 22, 23 must be made ineifective. To this end, weak springs 25 are provided which are adapted to lift the valve body 22 olf its seat 23 with such a force that said springs will overcome the force exerted by the plunger 19 which force is only small due to the low static pressure in the chamber 15. On the other hand, the force of the springs 25 is so low that it can be ignored at higher static pressures so that the pressure head will then always be substantially proportional to the static pressure in the main line. Thus, for instance, when the static pressure in'the' main line is .100 atii. (atmospheres above atmospheric pressure), the pressure head is atiil; likewise the pressure head willbe 9.5. atii. when the static pressure in the main lineis 10 atii.

According to the modification shown in Fig. 2,. the closing force ofthe stop valve 22a, 23a is produced by a bellows, spring.v Since, however, such small bellows springs as are required in this instanc'ecan hardly be produced, a larger v bellows spring 30 is opposed to a smaller bellows spring 31. The-bore 17a leads from below into the interconnected "bellows. The pressure ahead of the flow divider valve 8, 11 therefore has the tendency to stretch the bellows. The bellows springs are located in a chamber 32 corresponding to the chamber 13 while the bore 12a leads into the chamber 32 and while a passage 14a leads from the chamber 32 to the measuring instrument not shown. The bellows springs are thus loaded from the outside by the substantially even pressure behind the stop valve 22a, 23a. The bellows 31 rests against a member 33 the height of which may be varied by a screw bolt 34 from the outside in the manner evident from the drawing. A plate 35 is connected by means of arms 36 with a cup 37 receiving and supporting the valve body 22a and separates the bellows springs 30 and 31 from each other. The arms 36 are guided by protrusions 38 connected to the body la. It will be evident that with increasing pressure in the passage 17a and thus in the bellows, the axial force on the bellows spring 30 which is counteracted only partially by the axial force in the bellows springs 31 will press the valve body 22a with increased pressure against its seat 23a, thereby increasing the pressure head.

According to the modification shown in Fig. 3, the bellows springs of Fig. 2 have been replaced by a Bourdon spring 40 the interior of which is subjected to the pressure ahead of the flow divider valve whereas the outside of the Bourdon spring 40 is subjected to the pressure behind the stop valve 22b, 23b. The upper portion of the Bourdon spring 40 has a depression 41 engaged by a cone-shaped point 43 connected to the cup 42 which receives the valve body 22b. The cup 42 is provided with protruding wings 44 for guiding said cup in the chamber 32. In order to be able to regulate the thrust of the spring 40, the lower end of the spring 40 is supported by a stopper 45 which threadedly engages the casing 70 so as to be adjustable therein. The stopper 45 is provided with an annular groove 46 of such a width that within the range of adjustability of the stopper 45 the groove 46 will always communicate with the passage 17b. The annular groove 46 communicates with a bore 47 leading to the interior of the Bourdon tube or Bourdon spring so that fluid can pass from the passage 1712 through groove 46 and bore 47 into the interior of the Bourdon tube for purposes of stretching the same. Otherwise the function of the arrangement of Fig. 3 corresponds to that of Fig. 2.

With the modification according to Fig. 2 as well as with the modification according to Fig. 3, springs of the type designated with the reference numeral in Fig. 1 may be employed.

It is, of course, understood that the present invention is, by no means, limited to the particular constructions shown in the drawing but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In a flow divider for connection with a restrictorequipped flow pipe, the combination of: a casing, a diaphragm supported by said casing and subdividing the same into a first and a second chamber, said first chamher having passage means for connection with said flow pipe behind said restrictor, and said second chamber having passage means for connection with said flow pipe ahead of said restrictor, a valve seat member arranged in said casing and having a conduit therethrough for discharging a branch current from said second chamber, a valve member supported by said diaphragm for cooperation with said valve seat member to control the discharge of said branch current from said second chamber into said conduit, said casing being provided with an outlet for discharging said branch current and for connection with a measuring device, a stop valve member interposed between said outlet and said conduit and adapted to move into closing position for closing said conduit to prevent communication between the latter and said outlet and to create a pressure head for said branch current in said conduit, and channel means conveying the pressure prevailing in said second chamber to said valve member for causing the latter to close said conduit, said stop valve member being so designed that the maximum force adapted to be exerted thereupon for moving the same into closing position when said valve member is subjected to the pressure in said second chamber is less than the force exerted upon said valve member by said branch current when said conduit communicates with said second chamber.

2. In a flow divider for connection with a restrictorequipped flow pipe, the combination of: a casing, a diaphragm supported by said casing and subdividing the same into a first and a second chamber, said first chamber having passage means for connection with said flow pipe behind said restrictor, and said second chamber having passage means 'for connection with said flow pipe ahead of said restrictor, a valve seat member arranged in said casing and having a conduit therethrough for discharging a branch current from said second chamber, a valve member supported by said diaphragm for cooperation with said valve seat member to control the discharge of said branch current from said second chamber into said conduit, said casing being provided with an outlet for discharging said branch current and for connection with a measuring device, a stop valve interposed between said conduit and said outlet and adapted to interrupt fluid connection between said conduit and said outlet to build up a pressure head for said branch current in said conduit, said stop valve including a valve member for closing contact with said conduit and also including a Bourdon tube having one end connected to said valve member, and channel means conveying the pressure prevailing in said second chamber to said valve member for causing the latter to close said conduit, the other end of said Bourdon tube being open and in communication with said channel means, said stop valve including said Bourdon tube being so designed that the force adapted to be exerted thereupon for moving said valve member into closing position when the interior of said Bourdon tube is subjected to the pressure in said second chamber is less than the force exerted upon said valve member by said branch current when said conduit communicates with said second chamber.

3. A fiow divider according to claim 2, in which said other end of said Bourdon tube includes a plunger-like portion adjustable relative to said valve member for varying the thrust of said Bourdon tube.

4. In a flow divider for connection with a restrictorequipped fiow pipe, the combination of: a casing, a diaphragm supported by said casing and subdividing the same into a first chamber and a second chamber, said first chamber having passage means for connection with said flow pipe behind said restrictor, and said second chamber having passage means for connection with said flow pipe ahead of said restrictor, a valve seat member arranged in said casing and having a conduit therethrough for discharging a branch current from said second chamber, a valve supported by said diaphragm for cooperation with said valve seat member to control the discharge of said branch current from said second chamber into said conduit, said casing being provided with an outlet for discharging said branch current and for connection with a measuring device, a stop valve member interposed between said outlet and said conduit and adapted to move into closing position for closing said conduit to prevent communication between the latter and said outlet and to create a pressure head for said branch current in said conduit, a reciprocable plunger associated with said stop valve member, and channel means conveying the pressure prevailing in said second chamber to said plunger to cause said plunger to urge said stop valve member into its closing position, the cross section of said plunger as exposed to the pressure in said channel means being smaller than the effective cross section of said stop valve member as exposed to the pressure in said conduit.

5. In a flow divider for connection with a restrictorequipped fiow pipe, the combination of: a casing, a diaphragm supported by said casing and subdividing the same into a first and a second chamber, said first chamg her having passage means for connection with said flow pipe behind said restrictor, and said second chamber having passage means for connection with said flow pipe ahead of said restrictor, a valve seat member arranged in said casing and having a conduit therethrough for discharging a branch current from said second chamber, a first valve member supported by said diaphragm for cooperation with said valve seat member to control the discharge of said branch current from said second chamber into said conduit, said casing being provided with an outlet for discharging said branch current and for connection with a measuring device, a second valve member acting as stop valve member and interposed between said outlet and said conduit and adapted to move into closing position for closing said conduit to prevent communication between the latter and said outlet and to create a pressure head for said branch current in said conduit, bellows spring means supporting said stop valve member and having that end thereof which is adjacent said stop valve member closed, and channel means connected to the other end of said bellows spring means and conveying the pressure prevailing in said second chamber into said bellows spring means and thereby onto said stop valve member to cause the latter to close said conduit, said bellows spring means being so designed that the maximum force adapted to be exerted upon said second valve member for moving the same into closing position when said bellows spring means is subjected to the pessure in said second chamber is less than the force exerted upon said second valve member by said branch 3 current when said conduit communicates with said ond chamber.

6. A flow divider according to claim 5, in which said bellows spring means is composed of two superimposed bellows of different effective cross section, that bellows which is adjacent said stop valve member having an effective cross section less than the effective cross section of the other bellows.

7. A flow divider according to claim 5, in which said bellows spring means comprises a first bellows having one end stationarily but adjustably arranged, plate means connected to the other end of said bellows and connected to said stop valve member, and a second bellows having One end connected to said plate'means and having its other end fixedly connected to said casing, the diameter of said second bellows being greater than the diameter of said first bellows.

8. A flow divider according to claim 1, which includes relatively weak spring means continuously urging said step valve member to open.

References Cited in the file of this patent UNITED STATES PATENTS 1,407,993 Earl Feb. 28, 1922 1,623,431 NcVoy Apr. 5, 1927 2,018,119 Brouse Oct. 22, 1935 2,192,141 McElwaine Feb. 27, 1940 2,731,026 Hughes Jan. 17, 1956 

